Semiconductor device and method for manufacturing the same

ABSTRACT

To realize a high-performance liquid crystal display device or light-emitting element using a plastic film. A CPU is formed over a first glass substrate and then, separated from the first substrate. A pixel portion having a light-emitting element is formed over a second glass substrate, and then, separated from the second substrate. The both are bonded to each other. Therefore, high integration can be achieved. Further, in this case, the separated layer including the CPU serves also as a sealing layer of the light-emitting element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.12/266,589, filed Nov. 7, 2008, now allowed, which is a continuation ofU.S. application Ser. No. 10/795,445, filed Mar. 9, 2004, now U.S. Pat.No. 7,576,362, which claims the benefit of a foreign priorityapplication filed in Japan as Serial No. 2003-069742 on Mar. 14, 2003,all of which are incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device having a circuitincluding thin film transistors (hereinafter, TFT) and a method formanufacturing the same. Specifically, the present invention relates toelectronic devices incorporating an electro-optical device typified by aliquid crystal display panel, or a light emitting display device havingan organic light emitting element, as a component. In addition, thepresent invention relates also to a semiconductor device having acircuit including thin film transistors which are formed by transferringand bonding a layer which has been separated by a separation method, toa substrate.

It should be noted that the term “a semiconductor device” in thisspecification denotes all kinds of devices that can function byutilizing semiconducting properties, and includes all of anelectro-optical device, a semiconductor circuit, and electronics.

2. Description of the Related Art

In recent years, a technique for manufacturing a thin film transistor byusing a semiconductor thin film (from several nm to several hundred nmin thickness) that is formed over a substrate having an insulatingsurface has attracted a lot of attention. Such a thin film transistor isapplied to an electronic device such as an IC or an electro-opticaldevice widely, and developed intensively as a switching element of apicture display device in particular.

Various applications using such a picture display device have beenexpected, and particularly, application to a portable device attractsattention. As a substrate for forming these TFTs, a glass substrate or aquartz substrate is widely used now, however, these substrates have somedrawbacks such as being fragile and heavy. Further, these substrates areunsuitable for mass-production since it is difficult to use alarge-sized glass substrate or a large-sized quartz substrate. Thereforeit has been attempted that an element including TFTs is formed over asubstrate having flexibility as typified by a flexible plastic film.

However, the maximum temperature of the process should be lowered sincethe heat resistance of a plastic film is low. As a result, it has beenimpossible to form a TFT having as good characteristics as that formedover a glass substrate. Thus, a high-performance liquid crystal displaydevice or light emitting element using a plastic film has not beenrealized yet.

There has been proposed a method of separating from the substrate alayer to be separated that exists with a separation layer therebetween.For example, the technique stated in Patent Document 1 (JapanesePublished Unexamined Application No. Hei 10-125929) is that a separationlayer containing amorphous silicon (or, polysilicon) is provided, theamorphous silicon is irradiated with laser light through the substrate,to diffuse hydrogen included in the amorphous silicon, thereby producinga space to separate the substrate. In addition, in Patent Document 2(Japanese Published Unexamined Application No. Hei 10-125930), a liquidcrystal display device is completed by bonding a separated layer (alayer to be transferred in Patent Document 2) to a plastic film, byusing the technique of Patent Document 1.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems. It isan object of the present invention to make it possible to separate andtransfer an element having high electric property and a circuitincluding the elements, by a separation method by which a layer to beseparated is not damaged and by which a process of the layer to beseparated is not limited.

When a light emitting device and a liquid crystal display device inwhich an organic light emitting device is formed over a substrate havingflexibility such as a plastic film can be manufactured, the devices canbe thinned and lightweight, and further can be applied to a displayhaving a curved surface, a show window, or the like. Application of thedevices is not limited to a portable device, and is extremely wide.

According to the present invention, a separation method is carried outas follows: when a metal layer is formed over a substrate and an oxidelayer is laminated thereover, a metal oxide layer of the metal layer isformed in the interface of the metal layer and the oxide layer. Then,separation using the oxide metal layer is performed later.

Specifically, a tungsten film is formed by sputtering over a glasssubstrate, and a silicon oxide film is laminated by sputtering. When thesilicon oxide film is formed by sputtering, a tungsten oxide layer in anamorphous state is formed. And an element such as a TFT is formed overthe silicon oxide film. In the element formation process, the tungstenoxide layer is crystallized by a heat treatment of 400° C. or more. Byphysical force, separation occurs inside the tungsten oxide layer or inthe interface thereof. The layer (including an element such as a TFT)that is separated in this way is transferred to a plastic substrate.

When circuits having different functions are formed over the samesubstrate, it is difficult to manufacture the circuits in the sameprocess. When, for example, a pixel portion and a CPU are formed, apower supply voltage of the pixel portion for displaying (e.g., from 12V to 16 V) and a power supply voltage of the CPU (e.g., 5 V) aredifferent, it is difficult to manufacture the both over the samesubstrate. Accordingly, the steps get complex and the process yield isreduced.

According to the present invention, a plurality of separated layershaving different elements are provided, and the layers are bonded andelectrically connected to one another. An adhesive material includingdispersed conductive particles, which are represented by carbonparticles, silver particles, copper particles, or gold particles in anepoxy series adhesive material or a phenol series adhesive material, isused as an adhesive material for electrically connecting a plurality ofseparated layers. The adhesive material is patterned by a dispenserapplication method, offset printing or screen printing, and the layersare bonded to one another, and then baked.

For example, after forming a CPU over a first glass substrate, the CPUis separated from the first glass substrate. After forming a pixelportion having a light emitting element over a second glass substrate,the pixel portion is separated from the second glass substrate. Then,the CPU and the pixel portion are bonded to each other, therebyobtaining a highly integrated device. In this case, the separated layerincluding the CPU also serves as a sealing layer.

In the case of a bottom emission type light emitting device shown inFIG. 1A as an example, the CPU may be arranged to overlap with the pixelportion. Meanwhile, in the case of the top emission type light emittingdevice, or in the case of a dual emission type light emitting deviceshown in FIG. 1C, the CPU may be arranged not to overlap with the pixelportion.

In addition, a separated layer including a CPU is bonded to an opticalfilm, typified by a color filter, as shown as an example in FIG. 1D, andthe color filter is used as a support medium. The CPU is bonded to aportion except a portion functioning as the color filter, and the CPUbonded to the color filter is connected to wirings on the substrate sidethrough conductive particles included in the adhesive material. Anadhesive material including dispersed conductive particles representedby carbon particles, silver particles, copper particles, or goldparticles dispersedly in an epoxy series adhesive material or a phenolseries adhesive material, is used as the adhesive material forelectrically connecting a plurality of separated layers. The adhesivematerial is patterned by a dispenser application method, offset printingor screen printing, and the layers are bonded to one another, and thenbaked.

In the case of the bottom emission type light emitting device, theadhesive material for bonding the sealing layer may have the same heatradiation effect as a mould resin covering the CPU.

A configuration disclosed in the present invention is a semiconductordevice including: a substrate provided with a light emitting element,and a sealing plate provided with a semiconductor integrated circuit,wherein the substrate containing an organic resin material is bonded tothe sealing plate containing an organic resin material with a firstadhesive layer therebetween, a second adhesive layer is formed betweenthe light emitting element and the substrate, a third adhesive layer isformed between the semiconductor integrated circuit and the sealingplate, and a terminal electrode of the semiconductor integrated circuitis electrically connected to a terminal electrode over the substratethrough conductive particles.

Another configuration is a semiconductor device including: a substrateprovided with a pixel portion including a light emitting element and adriver circuit portion, and a sealing plate provided with asemiconductor integrated circuit, wherein the substrate containing anorganic resin material is bonded to the sealing plate containing anorganic resin material with a first adhesive layer therebetween, asecond adhesive layer is formed between the light emitting element andthe substrate, a third adhesive layer is formed between thesemiconductor integrated circuit and the sealing plate, and a display isperformed by making light from the light emitting element pass throughthe substrate.

In the above configuration, the semiconductor integrated circuit ispartially overlapped with the driver circuit portion or the pixelportion.

Another configuration is a semiconductor device including: a substrateprovided with a pixel portion including a light emitting element and adriver circuit portion, and a sealing plate provided with asemiconductor integrated circuit, wherein the substrate containing anorganic resin material is bonded to the sealing plate containing anorganic resin material with a first adhesive layer therebetween, asecond adhesive layer is formed between the light emitting element andthe substrate, a third adhesive layer is formed between thesemiconductor integrated circuit and the sealing plate, and a display isperformed by making light from the light emitting element pass throughthe sealing plate.

In the above configuration, a space between the substrate and thesealing plate is kept with a gap material such as fiber included in asealing material, and a region surrounded by the sealing material isfilled with the first adhesive layer or is filled with an inert gas andincludes a desiccant therein.

In the above configuration, the semiconductor integrated circuitincludes a central processing unit including a control unit and anarithmetic unit, and a memory unit, and the central processing unitincludes a plurality of thin film transistors.

In the above configuration, the semiconductor integrated circuitincludes at least a central processing unit including a control unit andan arithmetic unit, and a memory unit, and the sealing plate includes amemory element, a thin film diode, a silicon-based PIN junctionphotoelectric conversion element, a silicon resistance element, besidesthe central processing unit. As described above, it is effectiveparticularly for the case where a power supply voltage of a displayportion for displaying is different from a power supply voltage of asemiconductor integrated circuit (typically, a CPU) that a separationstep and a transfer step are performed in different steps and theresultant products are bonded to each other, instead of forming them inthe same process.

In the above configuration, the sealing plate is a film where alow-melting metal and ceramics are mixed into a synthetic resincontaining polypropylene, polypropylene sulfide, polycarbonate,polyether imide, polyphenylene sulfide, polyphenylene oxide,polysulfone, or polyphtal amide.

A configuration of the present invention for realizing the abovestructures is a method for manufacturing a semiconductor device,including the steps of: forming a layer to be separated including asemiconductor integrated circuit over a first substrate, separating thelayer to be separated including the semiconductor integrated circuitfrom the first substrate, transferring the separated layer including thesemiconductor integrated circuit to a second substrate, forming a layerto be separated including a display portion over a third substrate,separating the layer to be separated including the display portion fromthe third substrate, transferring the separated layer including thedisplay portion to a fourth substrate, and bonding the separated layerincluding the semiconductor integrated circuit to the separated layerincluding the display portion to obtain an assembly of the separatedlayers.

In the above configuration, the step of separating the layer to beseparated including the semiconductor integrated circuit from the firstsubstrate, and transferring to the second substrate, includes the stepsof: applying an organic resin film that is soluble in a solvent, overthe layer to be separated, sandwiching the layer to be separated and anorganic resin film with the first substrate and a fifth substrate bybonding the fifth substrate to the organic resin film by a firsttwo-sided tape, bonding a sixth substrate to the first substrate by asecond two-sided tape, separating the first substrate to which the sixthsubstrate is bonded, from the layer to be separated by a physical means,sandwiching the separated layer with the fifth substrate and the secondsubstrate by bonding the second substrate to the separated layer by afirst adhesive material, separating the fifth substrate from theseparated layer and the first two-sided tape, separating the firsttwo-sided tape from the separated layer, and removing the organic resinfilm by a solvent.

In the above configuration about the method of manufacturing, thesolvent is water or alcohol.

In the above configuration about the method of manufacturing, the firstsubstrate is a glass substrate, and the fifth substrate and the sixthsubstrate are a quartz substrate or a metal substrate.

In the above structures about the method of manufacturing, the secondsubstrate and the fourth substrate are plastic substrates.

Note that, a light emitting element (an EL element) includes a layercontaining an organic compound that emits light by applying an electricfield (hereinafter, an EL layer), an anode, and a cathode. Luminescencegenerated by an organic compound are fluorescence that generates uponreturning of electrons from the singlet excited state to the groundstate and phosphorescence that generates upon returning of electronsfrom the triplet excited state to the ground state. A light emittingdevice manufactured according to the present invention can employ theboth luminescence.

The light emitting element (EL element) including an EL layer has astructure in which a pair of electrodes sandwich the EL layertherebetween, and the EL layer, generally, has a laminated structure.Typically, a laminated structure laminating a hole transporting layer, alight emitting layer, an electron transporting layer in this order isknown. The structure provides greatly high luminous efficiency and isused in almost all light emitting devices that are under research anddevelopment now.

Another structure including an anode, a hole injecting layer, a holetransporting layer, a light emitting layer, and an electron transportinglayer in this order or including an anode, a hole injecting layer, ahole transporting layer, a light emitting layer, an electrontransporting layer, and an electron injecting layer in this order isalso applicable. Fluorescent pigments or the like can be doped to thelight emitting layer. Either a low molecular weight material or a highmolecular weight material can be used for forming these layers. Inaddition, an organic compound layer including an inorganic material maybe employed. In this specification, an EL layer is a generic term usedto refer to all layers formed between a cathode and an anode. Therefore,all of the above-mentioned hole injecting layer, hole transportinglayer, light emitting layer, electron transporting layer, and electroninjecting layer are included in an EL layer.

Further, there are no particular limitations placed on a method fordriving a screen display in the light emitting device of the presentinvention. For example, a dot sequential driving method, a linesequential driving method, a surface sequential driving method, or thelike may be used. A line sequential driving method is typically used,and a time division gray scale driving method or a surface area grayscale driving method may also be appropriately employed. Further, imagesignals input to a source line of the light emitting device may beeither analog signals or digital signals. Driving circuits and the likemay be appropriately designed according to the image signals.

The present invention can be applied to a passive matrix light emittingdevice as well as an active matrix light emitting device.

The present invention can be applied to a liquid crystal display device,and a structure is that a semiconductor device, wherein a substrateprovided with a pixel TFT and a pixel electrode is bonded to an opticalfilm provided with an opposite electrode and a semiconductor integratedcircuit, a liquid crystal material is filled between the substratecontaining an organic resin material and the optical film containing anorganic resin material, a second adhesive layer is formed between thepixel TFT and the substrate, a third adhesive layer is formed betweenthe semiconductor integrated circuit and the optical film, and aterminal electrode of the semiconductor integrated circuit iselectrically connected to a terminal electrode over the substrate byconductive particles.

The present invention also provides a method for laminating separatedlayers obtained by the separation method and for electrically connectingterminals that are provided for each of the separated layers.

According to the present invention, edge faces of the separated layersare disposed so that each terminal electrode thereof may be arranged ina staircase pattern, and fixed. The separated layers are laminated toexpose terminals thereof.

Complicated steps are required to connect the separated layers. Forexample, when three separated layers are overlapped with one another,and a terminal electrode is provided for a surface of a first separatedlayer, it is necessary to provide terminals for the both front side andback side of a second separated layer and to electrically connect theterminals.

According to the present invention, when three separated layers areoverlapped, terminal electrodes are provided for the surface of thefirst separated layer, the surface of the second separated layer, andthe surface of the third separated layer, respectively, as an exampleshown in FIG. 7A, and positions of the terminal electrodes are disposednot to be overlapped with one another, and the separated layers arebonded together. An anisotropic conductive film is bonded thereover in astaircase pattern, and further, an FPC is bonded to be in contact withthe film to make an electrical connection with the terminal electrodesof the separated layers. It should be noted that the anisotropicconductive film of this specification is a film in which conductiveparticles are mixed into a thermosetting or thermoplastic resin film,also referred to as an ACF (anisotropic conductive film). A two-layerACF or a three layer ACF may be employed. When the anisotropicconductive film is bonded to the assembly of the separated layers, stepsare formed. The FPC is bonded to be in contact with the steps, and theFPC has also a staircase pattern.

Alternatively, wirings (metal foil) that fit terminal pitch may beprovided on the surface of anisotropic conductive film, in this case, anFPC may be bonded, in accordance with the wirings on the surface of theanisotropic conductive film and the FPC is not required to be made in astaircase pattern.

Since the thickness of the separated layer obtained according to thepresent invention is thin (approximately 1.5 μm), the step differencebetween the separated layers is small, and conduction can be obtained bybonding the anisotropic film or the FPC in a staircase pattern bythermocompression in this way. Particularly, when terminals of commonwirings such as a ground wiring and a power supply wiring are arrangedlinearly, only one wiring of the FPC side or the anisotropic conductivefilm side is needed, thereby reducing the number of wirings.Alternatively, the conduction may be performed only among the separatedlayers that are laminated. According to the present invention, variouselectrical connections between layers, between exposed electrodes, andthe like are performed only by bonding the anisotropic conductive filmand the FPC. Thus, steps of electrical connection can be reduced and theprocess yield can be enhanced.

A configuration of the present invention by the above describedconnection is a semiconductor device, which is an assembly ofsemiconductor integrated circuits that are formed by overlapping andbonding a plurality of layers including a semiconductor element, whereineach layer including the semiconductor element has a terminal electrodeon a surface thereof, the layers including the semiconductor element arearranged in a staircase pattern in such a way that edge faces thereofare exposed, and bonded, and one anisotropic conductive film is bondedin a staircase pattern in accordance with the terminal electrode and theedge faces.

In the above configuration, the anisotropic conductive film or an FPChaving a staircase pattern is bonded to be in contact with all of theterminal electrodes, and a wiring provided for the anisotropicconductive film or a wiring provided for the FPC is electricallyconnected to the terminal electrode.

In the above configuration, the layer including the semiconductorelement is a layer that is separated from a glass substrate or a quartzsubstrate by a separation method.

Another configuration of the present invention by the above describedconnection is a semiconductor device including a light emitting elementthat has a layer containing an organic compound as a light emittinglayer, and a semiconductor element, wherein one layer of an inorganicinsulating film is included as a sealing layer of the light emittingelement that has the layer containing the organic compound as the lightemitting layer, and a layer including the semiconductor element isbonded thereto by an adhesive agent.

In the above configuration, the layer including one inorganic insulatinglayer and the semiconductor element is a layer that is separated from aglass substrate or a quartz substrate by the separation method.

In the above structure, the inorganic insulating film is a siliconnitride film or a silicon oxynitride film.

According to the present invention, a layer including a CPU is bonded toa sealing plate containing plastic, thereby achieving a higherintegration. Further, the CPU provided for the sealing plate can bemounted at the same time when an active matrix substrate and the sealingplate are bonded together with each other, and thus steps of mountingcan be reduced.

A support medium of the present invention can be more inexpensive,flexible, and light-weight.

These and other objects, features and advantages of the presentinvention become more apparent upon reading of the following detaileddescription along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1D show cross-sectional structures of the present invention,respectively (Embodiment Mode 1);

FIGS. 2A to 2E show manufacturing steps, respectively (Embodiment 1);

FIGS. 3A to 3J show manufacturing steps, respectively (Embodiment 1);

FIG. 4 is a block-diagram of a CPU (Embodiment Mode 2);

FIGS. 5A and 5B show a display side and a backside, respectively(Embodiment Mode 2);

FIGS. 6A and 6B show a top view and a cross sectional view of asemiconductor device, respectively (Embodiment 1);

FIGS. 7A and 7B are cross-sectional views of a semiconductor device,(Embodiment Mode 3);

FIGS. 8A and 8B are an oblique perspective view and a top view of abottom emission type light emitting device, respectively (Embodiment 4);

FIGS. 9A to 9E are examples of electronic devices, respectively(Embodiment 5); and

FIGS. 10A to 10C are examples of electronic devices, respectively(Embodiment 5).

DETAILED DESCRIPTION OF THE INVENTION

Embodiment modes of the present invention are described hereinafter.

Embodiment Mode 1

Here, a separation method using a metal film and a silicon oxide film isemployed. According to the present invention, an assembly of separatedlayers is formed by bonding a plurality of the separated layers obtainedby a separation method.

A semiconductor integrated circuit (here, CPU) 106, an insulating layer108, and a layer to be separated (a first layer to be separated)including a terminal electrode 111 are formed over a first substrate.The first layer to be separated includes a silicon nitride film servingas a blocking layer. A protective film or a gate insulating film may beformed from the silicon nitride film. The blocking layer is provided toprevent impurities (such as oxygen and moisture) from diffusing andentering from the outside.

The CPU includes an n-channel TFT, a p-channel TFT, a CMOS circuitcombining the both complementary, and a capacitor.

The first layer to be separated is separated from the first substrate,and transferred to a first plastic substrate 102 with a third adhesivelayer 103 c therebetween. In this stage, a sealing plate is completed. Aterminal electrode 110 that is an end portion of a wiring extending fromthe CPU is exposed.

After a layer to be separated (a second layer to be separated) includingan insulating film 104, TFTs is arranged in matrix, and one electrode ofa light emitting element which connect with the TFTs is formed over asecond substrate, the second layer to be separated is separated from thesecond substrate, and transferred to a second plastic substrate 101 withan adhesive layer 103 b therebetween. Thereafter, a light emitting layerand the other electrode of the light emitting element are formed tocomplete the light emitting element. In this stage, a pixel portion 105having the light emitting element is completed. In addition, a drivercircuit 107 may be formed in the same step as the TFTs arranged inmatrix. A terminal electrode 111 that is an end portion of a wiringextending from the pixel portion or the driver circuit is exposed.

Subsequently, the first plastic substrate and the second plasticsubstrate are bonded together with an adhesive material 112 (a sealingmaterial) including conductive particles so that the terminal electrodeswhich are provided for the first plastic substrate and the secondplastic substrate, respectively can be overlapped with each other. Ananisotropic conductive film (ACF) and a solder may be used instead ofthe adhesive material including conductive particles. Conduction amongthe terminal electrodes that are provided for the different substratescan be obtained by using the conductive particles. The sealing materialis preferably applied so as to surround the pixel portion 105, and aspace between the pair of the substrates is preferably filled with anadhesive material 103 a (a first adhesive layer) having lower viscositythan that of the sealing material. It is desirable in the reliability ofthe light emitting element to employ a material that can preventpenetration of oxygen and moisture as the adhesive material to fill theinside. Further, heat radiation of the semiconductor integrated circuitor the light emitting element can be performed when a material havinghigh heat conduction is used for the adhesive material 103 a.

According to the present invention, sealing of the light emittingelement and mounting of a semiconductor integrated circuit can beperformed at the same time.

In the case of a display device in which the light emitting direction ofthe light emitting element is a direction shown by an arrow in FIG. 1A,in such a way that light of the light emitting element passes throughthe second plastic substrate 101 (bottom emission type), there is noadverse effect of displaying when the semiconductor integrated circuit106 is overlapped with the pixel portion 105. Reference numeral 109denotes an FPC in FIG. 1A.

A space 114 between the pair of substrates is shown in a structure ofFIG. 1B. Here, a semiconductor integrated circuit 116 has a small size,but may have a size for partially overlapping with a portion of thepixel portion. Further, a desiccant for capturing moisture in the space,or a deoxidant for capturing oxygen may be disposed in the space 114.The same elements as those in FIG. 1A are denoted by the same referencenumerals as those in FIG. 1A.

As shown in FIG. 1C, in the case of a display device in which the lightemitting directions of the light emitting element are directions shownby arrows in FIG. 1C, in such a way that light of the light emittingelement passes through the first plastic substrate 101 and the secondplastic substrate 102 (dual emission type), the semiconductor integratedcircuit 116 is arranged so as not to overlap with a pixel portion 115.An adhesive material 113 to fill a space of the pair of substrates ispreferably made of a transparent material. The same elements as those inFIG. 1A are denoted by the same reference numeral as those in FIG. 1A.

The present invention can be applied to a passive matrix light emittingdevice as well as an active matrix light emitting device.

The present invention is useful for a liquid crystal display device aswell as a light emitting element. Instead of the first plasticsubstrate, an optical film (such as a polarization film or a phasedifference film) 122, for example, a color filter is used. In the colorfilter, colored layers of red, blue, and green are arranged inaccordance with a pixel, a black light-shielding layer is provided forthe space therebetween. The semiconductor integrated circuit 116 isarranged in portions other than the colored layers and the blacklight-shielding layer. As shown in FIG. 1D, an opposite electrode 121 isformed together with the semiconductor integrated circuit 116, and aseparation step and a transfer step are performed to provide a colorfilter. At this time, the optical film 122 serves as an oppositesubstrate and holds a liquid crystal material 120. It is noted that anorientation film (not shown) is provided to be in contact with theliquid crystal material 120. When bonding the color filter, alignment ofthe color filter is performed, and alignment of the terminal electrodesalso can be performed at the same time. The same elements as those inFIG. 1A. are denoted by the same reference numeral as those in FIG. 1A.

Embodiment Mode 2

In this embodiment mode, an example of forming a layer to be separatedincluding a memory or a central processing unit (referred to as a CPU)over a substrate (typically, a glass substrate, a quartz substrate)having an insulating surface, and then transferring to a plasticsubstrate is described with reference to FIG. 4 and FIGS. 5A and 5B.

In FIG. 4, reference numeral 1001 denotes a central processing unit(CPU), 1002 denotes a control unit, 1003 denotes an arithmetic unit,1004 denotes a memory unit (referred to as a memory), 1005 denotes aninput unit, and 1006 denotes an output unit (such as a display portion).

The central processing unit 1001 includes the control unit 1002 and thearithmetic unit 1003. The arithmetic unit 1003 comprises an arithmeticlogic unit (ALU) for performing arithmetic operations such as additionand subtraction, or logical operations such as AND, OR, and NOT, variousregisters for temporarily storing data or results of the operations, acounter for counting the number of 1 that are inputted, and the like.Circuits of the control unit 1003, such as an AND circuit, an ORcircuit, a NOT circuit, a buffer circuit, a resistor circuit can beformed from TFTs. For the sake of obtaining a high field effectmobility, a semiconductor film that has been crystallized by laser lightof a continuous wave laser may be formed as an active layer of the TFT.

A tungsten film and a silicon oxide film are formed over a substrate bysputtering, then a base insulating film (a silicon oxide film, a siliconnitride film, or a silicon oxynitride film) is formed thereover, andthen an amorphous silicon film is formed thereover. In a later step,separation is performed by using a tungsten oxide layer formed in theinterface between the tungsten film and the silicon oxide film.

Crystallization methods for obtaining a polysilicon film are given asfollows: a method of adding a metal element serving as a catalyst to theamorphous silicon film, heating the film to obtain a polysilicon filmand obtaining a more crystallized polysilicon film by irradiating withlaser light of a pulsed laser; a method of emitting laser light of acontinuous wave laser on the amorphous silicon film to obtain apolysilicon film; a method of heating the amorphous silicon film toobtain a polysilicon film and irradiating the polysilicon film withlaser light of a continuous wave laser to obtain a more crystallizedpolysilicon film; or a method of adding a metal element serving as acatalyst to the amorphous silicon film, heating the film to obtain apolysilicon film and obtaining a more crystallized polysilicon film byirradiating with laser light of a continuous wave laser. In the case ofusing a continuous wave laser, the direction of a channel length of aTFT constituting the arithmetic unit 1003, the control unit 1002 or thememory unit 1004 is the same as a scanning direction of laser light.

The control unit 1002 has a function of executing an instruction storedin the memory unit 1004 and controlling the whole operation. The controlunit 1002 includes a program counter, an instruction register, and acontrol signal generating unit. The control unit 1002 can be formed fromTFTs and a crystallized semiconductor films are used as active layers ofthe TFTs.

The memory unit 1004 is a unit for storing data and instructions forperforming operations. Data or programs that are often executed in theCPU are stored in the memory unit 1004. The memory unit 1004 includes amain memory, an address register, and a data register. A cache memorymay be used in addition to the main memory. These memories may includeSRAM, DRAM, a flash memory, or the like. When the memory unit 1004 isformed from TFTs, a crystallized semiconductor film is used as activelayers of the TFTs.

The input unit 1005 is a device for receiving data or program from theoutside. The output unit 1006 is a device for displaying results,typically, a display device.

The direction of the channel length of the TFT is the same as a scanningdirection of laser light, thereby making it possible to manufacture aCPU having less variation of characteristic over an insulatingsubstrate.

A layer to be separated including the thus obtained CPU (including aterminal electrode 1015 and leading wirings) is separated from thesubstrate and transferred to a plastic substrate 1016.

Similarly, a layer to be separated including a display portion 1011 anda driver circuit portion 1013 is formed over a substrate, and then,separated from the substrate, and transferred to a plastic substrate1010. A leading wiring from the driver circuit portion 1013, a terminalelectrode 1014 a and a terminal electrode 1014 b for electricallyconnecting to a terminal electrode 1015 of the CPU are provided.

The separated layer including the CPU, the separated layer including thedisplay portion 1011 and the driver circuit portion 1013 are bondedtogether by an adhesive material 1014. Thus, a semiconductor deviceincluding the assembly of the separated layers can be completed.

FIGS. 5A and 5B show a state in which the separated layers are bondedtogether. FIG. 5A shows a display surface side and an example of displaythat is performed by making light pass through the plastic substrate1010 provided with the driver circuit. FIG. 5B shows a backside and amode of the plastic substrate 1016 provided with the CPU.

The CPU and the terminal electrode 1014 b are electrically connectedwith each other via the conductive particles included in the adhesivematerial 1014. The display portion 1011 is sealed with the plasticsubstrate 1016 and the adhesive material 1014, thereby preventingimpurities from entering from the outside.

A region surrounded by the adhesive material 1014 may be filled with anorganic resin.

A protective film including a silicon nitride film is provided for thewhole surface of the substrate to cover the CPU, and thus, the wholesurface can neatly be separated in the separation step. This siliconnitride film can serve as a barrier film.

Here, the example of display that is performed by making light passthrough the plastic substrate 1010 is shown, but the present inventioncan be applied to the case of display that is performed by making lightpassing through the plastic substrate 1016. Further, the presentinvention can be also applied to the case of display that is performedby making light pass through both the plastic substrate 1010 and theplastic substrate 1016.

Embodiment Mode 3

Here, an electrical connection method of the present invention isdescribed with reference to FIGS. 7A and 7B.

According to Embodiment Mode 1, a first terminal electrode 711 a, adriver circuit portion 707, and a pixel portion 705 are formed over aresin substrate 701. Specifically, a tungsten film and a silicon oxidefilm (a layer of an insulating layer 704) are formed over a glasssubstrate by sputtering, and a base insulating film, the first terminalelectrode 711 a, TFTs (the pixel portion and the driver circuitportion), an anode, and a partition wall are sequentially formedthereover, and then, a quartz substrate is bonded to separate the glasssubstrate. The insulating layer 704 that has been separated is bonded tothe resin substrate 701 with a first adhesive layer 703 a therebetween.Then, the quartz substrate is removed. A layer containing an organiccompound and a cathode are formed over the anode to manufacture a lightemitting element, and the pixel portion 705 is formed by being coveredwith a protective film.

Similarly, a tungsten film and an silicon oxide film (a layer of aninsulating layer 700) are formed over a glass substrate by sputtering,and a base insulating film, a second terminal electrode 711 b, a firstsemiconductor integrated circuit 706 (such as a memory) are formedthereover, and then, a quartz substrate is bonded to separate the glasssubstrate. The insulating layer 700 that has been separated is bonded soas to cover the pixel portion provided for the resin substrate 701 witha second adhesive layer 703 b and a sealing material 702 therebetween.Then, the quartz substrate is removed. When the second adhesive layer703 b is used to bond, edge faces are disposed to expose at least aportion of the first terminal electrode 711 a. Further, the insulatinglayer 700 includes at least either a silicon nitride film or a siliconoxynitride film, and thus, the film can have an effect of a blockinglayer.

Similarly, a tungsten film and a silicon oxide film (a layer of aninsulating layer 708) are formed over a glass substrate by sputtering,and a base insulating film, a third terminal electrode 711 c, a secondsemiconductor integrated circuit 709 (such as a CPU) are formedthereover, and then, a quartz substrate is bonded to separate the glasssubstrate. The insulating layer 708 that has been separated is bonded soas to cover the memory with a third adhesive layer 703 c therebetween.Then, the quartz substrate is removed. When the third adhesive layer 703c is used to bond, edge faces are disposed to expose a portion of thesecond terminal electrode 711 b. Further, the insulating layer 708includes at least either a silicon nitride film or a silicon oxynitridefilm, and thus, the film can have an effect of a blocking layer.

According to the above-described steps, as shown in FIG. 7A, threeseparated layers are overlapped over the resin substrate 701 to obtain astructure in which the terminal electrodes 711 a to 711 c are arrangedin a staircase pattern.

Lastly, an anisotropic conductive film 712 is bonded to the terminalelectrodes 711 a to 711 c to perform thermocompression on an FPC 718. Asshown in FIG. 7A, since the terminal electrodes 711 a to 711 c arearranged in a staircase pattern, the anisotropic conductive film 712 hasalso a staircase pattern in accordance with the step differences of theterminal electrodes. In addition, a wiring pattern (e.g., aluminum foil)may be formed on a surface of the anisotropic conductive film 712 toelectrically connect with each of the terminal electrodes bonded to thebackside face.

The light emitting direction in FIG. 7A is a direction for making lightpass through the resin substrate. The semiconductor integrated circuitalso can serve as a light-shielding film. When a metal material thatcannot transmit light is used as the cathode or the anode of the lightemitting element, the cathode or the anode of the light emitting elementcan function also as a light-shielding film to protect the semiconductorintegrated circuit from outside light.

A semiconductor integrated circuit such as a CPU generating much heat ispreferably arranged in a top layer to easily radiate the heat.

FIG. 7A shows a structure in which a separation step and a transfer stepare performed three times, respectively. However, the present inventionis not limited to the three-layer structure, and may adopt a structureshown in FIG. 7B.

In FIG. 7B, a semiconductor integrated circuit 713 is bonded byperforming a separation step and a transfer step once, in order to seala pixel portion 715 formed over a substrate 710 that is a glasssubstrate, a quartz substrate, or the like.

A first terminal electrode 721 a, a driver circuit portion 717, and apixel portion 715 are formed over the substrate 710 by a knowntechnique. Specifically, a base insulating film 724, the first terminalelectrode 721 a, TFTs (a pixel portion and a driver circuit portion), ananode, a partition wall, a layer containing an organic compound, and acathode are sequentially formed.

According to Embodiment Mode 1, a tungsten film and a silicon oxide film(a layer of an insulating layer 716) are formed over the glass substrateby sputtering, and the base insulating film, a second terminal electrode721 b, a semiconductor integrated circuit 713 including TFTs (such as amemory or a CPU) are formed thereover, and then, a quartz substrate isbonded with a second adhesive layer 723 b therebetween to separate theglass substrate. The insulating layer 716 that has been separated isbonded so as to cover the pixel portion provided for the substrate 710with a first adhesive layer 723 a therebetween and by a sealing material714. Then, the quartz substrate is removed. When the first adhesivelayer 723 a is used to bond, edge faces are disposed to expose even aportion of the first terminal electrode 721 a. Further, the insulatinglayer 716 includes at least either a silicon nitride film or a siliconoxynitride film, and thus, the film can have an effect of a blockinglayer.

According to the above-described steps, as shown in FIG. 7B, a structurein which a separated layer is overlapped over the substrate 710, and theterminal electrodes 721 a and 721 b are arranged in a staircase pattern.

Lastly, an anisotropic conductive film 722 is bonded to the terminalelectrodes 721 a and 721 b a thermocompression of an FPC 719 thereon isperformed. As shown in FIG. 7B since the terminal electrodes 721 a and721 b are arranged in a staircase pattern, the anisotropic conductivefilm 722 has also a staircase pattern in accordance with the stepdifferences of the terminal electrodes. In addition, a wiring pattern(e.g., aluminum foil) is formed on a surface of the anisotropicconductive film 722 to electrically connect with each of the terminalelectrodes bonded to the backside face. Here, it is not required toprovide the FPC 719 with a staircase pattern, since the wiring pattern(not shown) is formed on the surface of the anisotropic conductive film722.

This embodiment mode can be freely combined with Embodiment Modes 1 or2.

The present invention having the above described structures is describedin detail in embodiments that is described hereinafter.

EMBODIMENTS Embodiment 1

This embodiment shows an example of manufacturing an assembly ofseparated layers by the plurality of separated layers obtained by aseparation technique and a transfer technique.

Here, a separation method using a metal film and a silicon oxide film isadopted.

An element is formed over a glass substrate (a first substrate 200). Inthis embodiment, AN100 is used as the glass substrate. A metal film 201a is formed, here, a tungsten film is formed as the metal film 201 a tohave a thickness of from 10 nm to 200 nm, preferably, from 50 nm to 75nm by sputtering over the glass substrate. Further, an oxide film 202, asilicon oxide film in this instance, is laminated to have a thickness offrom 150 nm to 200 nm without being exposed to the air. The oxide film202 is preferably twice as thick as the metal film or more. It should benoted that a 2-nm to 5-nm-thick metal oxide film (a tungsten oxide film)in amorphous state is formed between the metal film 201 a and thesilicon oxide film 202 in laminating the silicon oxide film. Separationoccurs inside the tungsten oxide film, in the interface between thetungsten oxide film and the silicon oxide film, or the interface betweenthe tungsten oxide film and the tungsten film in a later separationstep. As materials for the metal layer, an element selected from thegroup consisting of Ti, Ta, Mo, Nd, Ni, Co, Zr, Zn, Ru, Rh, Pd, Os, Ir,and Pt; a single layer containing an alloy material or a compoundmaterial, each of which contains these elements as their maincomponents; a lamination layer of the single lavers; or nitrides, forexample, a single layer or a lamination layer formed from titaniumnitride, tungsten nitride, tantalum nitride, or molybdenum nitride maybe used.

The tungsten film, the tungsten oxide film and the silicon oxide filmare formed in the edge faces of the substrate by sputtering, and thus,preferably, removed by O₂ ashing selectively.

Next, a silicon oxynitride film as a base insulating film (with athickness of 100 nm) is formed by PCVD, and an amorphous silicon film(with a thickness of 54 nm) containing hydrogen is laminated thereoverwithout exposing to the air. Note that, the silicon oxynitride film is ablocking layer which prevents impurities such as alkali metal fromdiffusing out of the glass substrate.

A hydrogen concentration of the amorphous silicon film containinghydrogen was measured by FT-IR. As a result, Si—H was 1.06×10²²(atoms/cm³), Si—H₂ was 8.34×10¹⁹ (atoms/cm³), and the calculatedhydrogen concentration in the composition ratio was 21.5%. Further, thehydrogen concentration was similarly calculated under changed filmdeposition conditions for PCVD; results of the obtained hydrogenconcentrations in the composition ratio were 16.4%, 17.1%, and 19.0%.

Thereafter, the amorphous silicon film is crystallized by using a knowntechnique (solid-phase growth, laser crystallization, crystallizationusing a catalyst metal, or the like), and an element using a TFT havinga polysilicon film as an active layer is formed. In this embodiment, thepolysilicon film is obtained by crystallization using a catalyst metal.A nickel acetate solution containing nickel of 10 ppm is applied by aspinner. Nickel elements may be applied over the entire surface bysputtering instead of spin coating. Then, a heat treatment is carriedout to crystallize and form a semiconductor film having a crystalstructure (here, a polysilicon layer). In this embodiment, a siliconfilm having a crystal structure is obtained by a heat treatment forcrystallization (at 550° C. for 4 hours) after another heat treatment(at 500° C. for one hour).

The amorphous silicon film contains hydrogen. In the case of forming thepolysilicon film by heating, a heat treatment of 410° C. or more isperformed for crystallization, thereby diffusing hydrogen as well asforming the polysilicon film. A metal oxide film in an amorphous stateis crystallized by a heat treatment of 400° C. or more, therebyobtaining a metal oxide film 301 b having a crystal structure.Accordingly, the heat treatment of 410° C. or more makes it possible toform the metal oxide film having a crystal structure and diffusehydrogen. After the heat treatment of 410° C. or more is finished, theseparation inside the tungsten oxide film, or in the interface betweenthe tungsten oxide film and the silicon oxide film, or the interfacebetween the tungsten oxide film and the tungsten film can be achievedwith relatively little force (for example, human hands, wind pressure ofgas blown from a nozzle, ultrasonic waves, or the like). Note that, whena heat treatment is performed at a temperature at which a metal oxidefilm having a crystal structure can be obtained, the composition of theoxide metal film is changed and the thickness thereof is less to someextent. Further, the tungsten oxide film having a crystal structure hasa plurality of crystal structures (WO₂, WO₃, WO_(x) (2<X<3)), and WO₃ ischanged into WO₂, or WO_(x) depending on the heat treatment in itscomposition.

Various elements typified by a TFT (a thin film diode, a silicon-basedPIN junction photoelectric conversion element, a sensor device(typically, a pressure-sensitive fingerprints sensor using polysilicon))can be formed by using the obtained polysilicon film. In addition, thepresent invention can be applied to an element having a TFT that uses anamorphous silicon film as an active layer, in the case of performing theheat treatment of 410° C. or more without being crystallized.

Next, after the oxide film on the surface of the silicon film having acrystal structure is removed by dilute hydrofluoric acid or the like,irradiation of laser light (XeCl: wavelength of 308 nm) for raising acrystallization rate and repairing defects remained in crystal grains isperformed in the atmosphere or in an oxygen atmosphere. Excimer laserlight with a wavelength of 400 nm or less, or a second harmonic wave ora third harmonic wave of a YAG laser is used for the laser light. Here,pulsed laser light with a repetition frequency of approximately from 10Hz to 1000 Hz is used, the pulsed laser light is condensed to from 100mJ/cm² to 500 mJ/cm² by an optical system, and irradiation is performedwith an overlap ratio of from 90% to 95%, thereby scanning the siliconfilm surface. Here, the irradiation of the laser light is performed inthe atmosphere with a repetition frequency of 30 Hz and energy densityof 470 mJ/cm². Note that, an oxide film is formed on the surface by thelaser light irradiation since the irradiation is conducted in theatmosphere or in an oxygen atmosphere. Though an example of using thepulsed laser is shown here, the continuous wave laser may also be used.When crystallization of an amorphous semiconductor film is conducted, itis preferable that the second harmonic through the fourth harmonic offundamental waves is applied by using a solid-state laser which iscapable of continuously oscillating in order to obtain a crystal inlarge grain size. Typically, it is preferable that the second harmonic(532 nm) or the third harmonic (355 nm) of an Nd: YVO₄ laser(fundamental wave of 1064 nm) is applied. Specifically, in the case ofusing the continuous wave laser, laser light emitted from the continuouswave type YVO₄ laser with 10 W output is converted into harmonics byusing a non-linear optical elements. Also, a method of emittingharmonics by applying crystal of YVO₄ and the non-linear opticalelements into a resonator can be given. Then, preferably, the laserlight is shaped so as to have a rectangular shape or an elliptical shapeby an optical system on the irradiated surface, thereby irradiating anobject to be treated. At this time, the energy density of approximatelyfrom 0.01 MW/cm² to 100 MW/cm² (preferably, from 0.1 MW/cm² to 10MW/cm²) is required. The semiconductor film is moved at approximatelyfrom 10 to 2000 cm/s rate relatively corresponding to the laser light soas to irradiate the semiconductor film.

The oxide film formed by this laser light irradiation and an oxide filmformed by treating the surface with ozone water for 120 seconds togethermake up a barrier layer that has a thickness of from 1 nm to 5 nm intotal. The barrier layer is formed in order to remove nickel that isadded for crystallization from the film. Though the barrier layer isformed by using ozone water in this embodiment, another method such asultraviolet irradiation in an oxygen atmosphere or oxygen plasmatreatment to oxidize the surface of the semiconductor film having thecrystal structure may be used. In addition, as another method forfarming the barrier layer, an oxide film having a thickness of aboutfrom 1 nm to 10 nm may be deposited by plasma CVD, sputtering,evaporation, or the like. Further, before forming the barrier layer, theoxide film formed by laser light irradiation may be removed.

On the barrier layer, an amorphous silicon film containing an argonelement is formed to have a thickness of from 10 nm to 400 nm, in thisembodiment, 100 nm by sputtering to serve as a gettering site. In thisembodiment, the amorphous silicon film containing the argon element isformed in an atmosphere containing argon by using a silicon target. Whenplasma CVD is performed for forming the amorphous silicon filmcontaining the argon element, the deposition conditions are as follows:a flow ratio of monosilane to argon (SiH₄:Ar) is controlled to be 1:99,a deposition pressure is 6.665 Pa (0.05 Torr), a RF power density duringthe deposition is 0.087 W/cm², and a deposition temperature is 350° C.

Thereafter, a furnace heated up to 650° C. is used for a heat treatmentfor 3 minutes for gettering to reduce the nickel concentration in thesemiconductor film having a crystal structure. A lamp annealingapparatus may be used instead of the furnace.

Subsequently, the amorphous silicon film containing the argon element,which is the gettering site, is selectively removed by using the barrierlayer as an etching stopper, and then, the barrier layer is selectivelyremoved by dilute hydrofluoric acid. Note that there is a tendency thatnickel is likely to move into a region with a high oxygen concentrationin gettering, and thus, it is desirable that the barrier layer made ofthe oxide film is removed after gettering.

Note, that, in the case where crystallization is not performed using acatalyst element, the above described steps such as the formation of thebarrier layer, the formation of the gettering site, the heat treatmentfor gettering, the removal of the gettering site, or the removal of thebarrier layer are not necessary.

Then, after a thin oxide film is formed from ozone water on the surfaceof the obtained silicon film having the crystal structure (also referredto as a polysilicon film), a mask made of resist is formed, and anetching treatment is conducted thereto to obtain a desired shape,thereby forming island-like semiconductor layers separated from oneanother. After the formation of the semiconductor layer, the mask madeof resist is removed.

Next, the oxide film is removed with etchant containing hydrofluoricacid, and at the same time, the surface of the silicon film is washed.Thereafter, an insulating film containing silicon as its main component,which serves as a gate insulating film, is formed. In this embodiment, asilicon oxynitride film (composition ratio: Si=32%, O=59%, N=7%, H=2%)is formed to have a thickness of 115 nm by plasma CVD.

Thereafter, gate electrodes are formed over a gate insulating film; theformation of a source region or a drain region attained by doping to anactive layer, the formation of an interlayer insulating film, theformation of a source electrode or a gate electrode, an activationtreatment, and the like are performed appropriately, therebymanufacturing top gate TFTs 203 a and 203 b which have a polysiliconfilm as an active layer. At the same time, a capacitor 206 can beformed. In addition, a semiconductor integrated circuit such as a CPUalso can be formed by combining them. It should be noted that othercircuits can be formed over the same substrate, although the p-channelTFT 203 a and the n-channel 203 b that constitutes the CMOS circuit areshown in FIGS. 2A to 2E.

A silicon nitride film or a silicon oxynitride film is formed as aprotective film 204 for covering TFT. Hydrogen is preferably containedin the protective film. A silicon nitride film for covering the CPU isprovided, as the protective film, for a whole surface of the substrate,thereby separating the whole surface cleanly in a separation step. Theprotective film 204 can also serve as a barrier layer of the lightemitting element.

Here, although not shown, terminal electrodes are formed at the sametime as the TFTs, and the terminal electrodes are exposed.

Next, an adhesive material that is soluble in water or alcohol isapplied over the whole surface and baked. The adhesive material may be,for example, epoxy series, acrylate series, silicone series, or thelike. Here, a film formed of water-soluble resin (TOAGOSEI Co., Ltd.:VL-WSHL10) 205 is spin-coated to have a thickness of 30 μm, and exposedfor two minutes to be temporarily cured, then, exposed its back side toUV rays for 2.5 minutes, and then, exposed its front side for 10 minutesto be fully cured (FIG. 2A). The exposure to light is performed for 12.5minutes in total. The water-soluble resin film serves as a levelingfilm, which can bond substrates to each other so that a surface of theleveling film and the substrate surface are placed in parallel inbonding the substrates later. There is a risk of unevenness that resultsfrom an electrode or from a TFT in pressure bonding when thewater-soluble resin film is not used.

The adhesiveness of the metal film 201 a and the metal oxide film 201 b,or the adhesiveness of the metal oxide film 201 b and an oxide film 202is partly weakened for easy separation in a later step. The treatmentfor partly weakening the adhesiveness is carried out by partly applyinglaser light to the metal oxide film 201 b along the region to beseparated, or damaging the inside or a part of the interface of themetal oxide film 201 b by applying pressure locally from outside alongthe region to be separated. Specifically, a hard needle such as adiamond pen may be pressed perpendicularly to the region to beseparated, and moved along with the periphery thereof by applyingloading. Preferably, a scriber device can be used to move with applyingloading on the region with thrusting in ranging from 0.1 mm to 2 mm. Itis important to carry out some steps for easy separation, that is, toprepare for the separation step. Such preparatory steps for weakeningselectively (partly) the adhesiveness prevents poor separation andimprove process yield.

Next, a second substrate 216 is bonded to a film 205 containingwater-soluble resin with a two-sided tape 215. Then, a third substrate210 is bonded to the first substrate 200 with a two-sided tape 209 (FIG.2B). The third substrate 210 prevents the first substrate 200 from beingdamaged in the later separation step. For the second substrate 216 andthe third substrate 210, the substrate that has higher rigidity thanthat of the first substrate 200, for example, a quartz substrate or asemiconductor substrate, is preferably to be used. Note that, anadhesive material which is separated by being exposed to ultravioletirradiation may be used instead of the two-sided tape.

The first substrate 200 provided with the metal film 201 a is separatedfrom the region, whose adhesiveness is partly weakened, by a physicalmeans. The first substrate 200 can be separated by relatively littleforce (for example, man's hand, air pressure of gas sprayed from anozzle, ultrasonic waves, or the like). Thus, a layer to be separatedformed on the silicon oxide layer 202 can be separated from the firstsubstrate 200. FIG. 2C shows a state after the separation step. Afterthe separation step, whole WO₂ remains in the first substrate, one-thirdof WO₃ remains in the first substrate, and two-thirds of WO₃ remains onthe separated layer side. The separation tends to occur in the tungstenoxide film, particularly, in the boundary of WO₂ and WO_(x), or theboundary of WO₂ and WO₃. The tungsten oxide film partly remains in theseparated layer, however, the tungsten film is transparent, so that thetungsten film may not be necessarily removed. In this embodiment, thetungsten film is removed.

By applying the separation method described above, a TFT having highelectric characteristics, which can be obtained over a glass substrate,(typified by field effect mobility) can be transferred to a plasticsubstrate, as it is.

Next, a fourth substrate 218 is bonded to the oxide layer 202 (and theseparated layer) with an adhesive material 217 (FIG. 2D). It isimportant for the adhesive agent 217 that the adhesiveness of the fourthsubstrate 218 and the oxide layer 202 (and the separated layer) isstronger than that of the second substrate 216 and the separated layerby the two-sided tape 215.

A plastic substrate (ARTON made of norbornene resin with a polar group,manufactured by JSR corporation) is used for the fourth substrate 218.The plastic substrate can be formed of polyethylene terephthalate (PET),polyether sulfone (PES), polyethylene naphthalate (PEN), polycarbonate(PC), nylon, polyether ether ketone (PEEK), polysulfone (PSF), polyetherimide (PEI), polyallylate (PAR), polybutylene terephthalate (PBT), orpolyimide.

As the adhesive material 217, various types of curing adhesive material,for example, a reaction-curing adhesive material, a heat-curing adhesivematerial, a photo-curing adhesive material such as a UV-curing adhesivematerial, or an anaerobic adhesive material etc. can be utilized.

The second substrate 216 is separated from the two-sided tape 215. Then,the two-sided tape 215 is removed. And then, the water-soluble resin 205is dissolved in water and removed (FIG. 2E).

According to the above-described steps, the first separated layer thatis transferred to the plastic substrate 218 is obtained.

Subsequently, a second layer to be separated is provided.

An element is formed over a glass substrate (a first substrate 300). Ametal layer 301 a is formed, here, a tungsten film is formed as themetal layer 301 a to have a thickness of from 10 nm to 200 nm,preferably, from 50 nm to 75 nm, as the first separated layer. Further,the oxide layer 302, a silicon oxide layer in this instance, islaminated to have a thickness of from 150 nm to 200 nm without beingexposed to the air.

Next, a silicon oxynitride film as a base insulating film (with athickness of 100 nm) is formed by PCVD, and an amorphous silicon film(with a thickness of 54 nm) containing hydrogen is laminated thereoverwithout exposing to the air.

Thereafter, the amorphous silicon film is crystallized by using a knowntechnique (solid-phase growth, laser crystallization, crystallizationusing a catalyst metal, or the like), and an element using a TFT havinga polysilicon film as an active layer is formed. A gate insulating filmand a gate electrode are formed; the formation of a source region or adrain region attained by doping to the active layer, the formation of aninterlayer insulating film, the formation of a source electrode or agate electrode, an activation treatment, and the like are performedappropriately, thereby manufacturing a top gate TFT 303 which has apolysilicon film as an active layer. Note that, a switching TFT or adriver circuit for driving a pixel portion is also formed over the samesubstrate, although only a current control TFT in the pixel portion isshown in FIGS. 3A to 3J.

Next, a layer containing an organic compound (hereinafter, an EL layer)is interposed between a pair of electrodes (an anode and a cathode).Then, a first electrode for forming a light emitting device that canachieve fluorescence or phosphorescence by applying electric field tothe pair of electrodes is formed. Here, the first electrode 304 that canserve as an anode or a cathode is formed of a metal film having a largework function (Cr, Pt, W, or the like), or a transparent conductive film(indium tin oxide alloy (ITO), indium oxide zinc oxide alloy(In₂O₃—ZnO), zinc oxide (ZnO), or the like). An example of forming thefirst electrode 304 for serving as an anode is described.

In the case where the source electrode or the drain electrode of a TFTserves as a first electrode, or a first electrode is formed separatelyto be in contact with the source region or the drain region, the TFTincludes the first electrode.

A partition wall 305 a (referred to as a bank, a barrier, a mound) isformed on each end of the first electrode (anode) to surround theperiphery of the first electrode. To improve the coverage, the upperedge portion or the bottom edge portion of the partition wall is formedto have a curved surface having curvature. For example, in the casewhere a positive type photosensitive acrylic is used as a material forthe partition wall, it is preferable that only the upper edge portion ofthe partition wall is formed to have a curved surface having radius ofcurvature (from 0.2 μm to 3 μm). Either a negative type resin that isinsoluble in etchant due to light or a positive type resin that isdissoluble in etchant due to light can be used as the partition wall 305a.

Further, in the case of laminating a plurality of organic resins, thereis a risk that a part of the plural organic resins is melted or theadhesiveness gets too high, during application or baking. Therefore, inthe case of using organic resin as a material for the partition wall,the partition wall 305 a is preferably covered with an inorganicinsulating film (a SiN_(x) film, a SiN_(x)O_(y) film, an AlN_(x) film,or an AlN_(x)O_(y) film) in order to make it easy to removewater-soluble resin after applying it over the surface in a later step.The inorganic insulating film serves as a part of the partition wall 305b (FIG. 3A).

Next, an adhesive material that is soluble in water or alcohol isapplied over the whole surface and baked. The adhesive material may be,for example, epoxy series, acrylate series, silicone series, or thelike. Here, a film formed of water-soluble resin (TOAGOSEI Co., Ltd.:VL-WSHL10) 306 is spin-coated to have a thickness of 30 μm, exposed fortwo minutes to be temporarily cured, and then, its back side is exposedto UV rays for 2.5 minutes, and then, its front side is exposed to UVrays for 10 minutes to be fully cured (FIG. 3B). The exposure to lightis performed for 12.5 minutes in total.

The adhesiveness of the metal film 301 a and the metal oxide film 301 b,or the adhesiveness of the metal oxide film 301 b and an oxide film 302is partly weakened for easy separation in a later step.

Next, a second substrate 308 is bonded to the film 306 formed ofwater-soluble resin with a two-sided tape 307. Then, a third substrate310 is pasted to the first substrate 300 with a two-sided tape 309 (FIG.3C). The third substrate 310 prevents the first substrate 300 from beingdamaged in the later separation step. For the second substrate 308 andthe third substrate 310, the substrate that has higher rigidity thanthat of the first substrate 300, for example, a quartz substrate or asemiconductor substrate, is preferably used. Note that, an adhesivematerial which is separated by being exposed to UV irradiation may beused instead of the two-sided tape.

The first substrate 300 provided with the metal film 301 a is separatedfrom the region, whose adhesiveness is partly weakened, by a physicalmeans. The first substrate 300 can be separated by relatively littleforce (for example, man's hand, air pressure of gas sprayed from anozzle, ultrasonic waves, or the like). Thus, a layer to be separatedformed over the silicon oxide layer 302 can be separated from the firstsubstrate 300. The tungsten oxide film partly remains in the separatedlayer, however, the tungsten film is transparent, so that the tungstenfilm may not be necessarily removed. In this embodiment, the tungstenfilm is removed.

Next, a fourth substrate 312 is bonded to the oxide layer 302 (and theseparated layer) with an adhesive material 311 (FIG. 3E). It isimportant for the adhesive material 311 that the adhesiveness of afourth substrate 312 and the oxide layer 302 (and the separated layer)is stronger than that of the second substrate 308 and the separatedlayer by the two-sided tape 307.

A plastic substrate (ARTON made of norbornene resin with a polar group,manufactured by JSR corporation) is used for the fourth substrate 312.The plastic substrate can be formed of polyethylene terephthalate (PET),polyether sulfone (PES), polyethylene naphthalate (PEN), polycarbonate(PC), nylon, polyether ether ketone (PEEK), polysulfone (PSF), polyetherimide (PEI), polyallylate (PAR), polybutylene terephthalate (PBT), orpolyimide.

As the adhesive material 311, various types of curing adhesivematerials, for example, a reaction-curing adhesive material, aheat-curing adhesive material, a photo-curing adhesive material such asa UV-curing adhesive material, or an anaerobic adhesive material etc. isutilized.

The second substrate 308 is separated from the two-sided tape 307 (FIG.3F).

Then, the two-sided tape 307 is removed (FIG. 3G).

And then, the water-soluble resin 306 is dissolved in water and removed(FIG. 3H). If residue of the water-soluble resin is left on the firstelectrode 304, it may cause the deterioration of the device.Consequently, it is preferable that the surface of the first electrode304 be rinsed or treated in O₂ plasma.

If necessary, the surface of the first electrode 304 is rubbed andwashed by using a porous sponge (typically, a sponge of PVA (polyvinylalcohol) or nylon) soaked in a surfactant (weak alkaline).

Immediately prior to forming a layer containing an organic compound (ELlayer) 313, the substrate is heated in a vacuum for removing moistureabsorbed in the whole substrate that is provided with a TFT and apartition wall. Moreover, the first electrode may be exposed toultraviolet irradiation immediately prior to forming the layercontaining the organic compound.

The layer containing the organic compound (EL layer) 313 is formedselectively over the first electrode (anode) by evaporation using anevaporation mask or ink-jetting. As the layer containing the organiccompound 313, a high molecular weight material, a low molecular weightmaterial, an inorganic material, a mixed layer formed of the abovematerials, a layer formed by dispersing the above materials, or alamination layer formed by stacking appropriate combination of the abovematerials can be used.

A second electrode (cathode) 314 is formed over the layer containing theorganic compound (FIG. 31). A thin film, which has a thickness of beingtransparent to light, formed of a small work function material (Al, Ag,Li, Ca, or alloy such as MgAg, MgIn, AlLi, or inorganic materials suchas CaF₂, or CaN) is utilized for the cathode 314. If necessary, aprotective layer is formed for covering the second electrode bysputtering or evaporation. The protective layer may contain a siliconnitride film, silicon oxide film, a silicon nitride oxide film (SiNOfilm: a ratio of N to O composition is N>O)), or silicon oxynitride(SiON film: a ratio of N to O composition is N<O), or a thin filmcontaining carbon as its main component (for example, DLC film, or CNfilm) that are formed by sputtering or CVD.

According to the above-described steps, the second separated layer thatis transferred to the plastic substrate 312 is obtained.

The thus obtained separated layers are bonded with each other. Here, thesame plastic substrates (ARTON manufactured by JSR corporation) are usedto prevent a warp by conforming the thermal expansion coefficient. Asealing material (not shown) containing a gap material for maintaining aspace between a pair of substrates is applied to the substrate 218 thatserves as a sealing plate. Conduction of terminal electrodes that areprovided for each of the two separated layers is obtained by conductiveparticles contained in the sealing material. For the conduction of theterminal electrodes, a conductive paste may be used separately from thesealing material.

Then, a few drops of a sealing material with a low viscosity are appliedand the substrate 218 and the active matrix substrate 312 are bondedwithout air bubbles mixed into the sealing material using a bondingdevice. It is preferable to bond the substrates in vacuum so as not togenerate bubbles. Moreover, the method for applying a few drops of thesealing material with a low viscosity is also effective for bonding apair of flexible plastic substrates together. Sealing is performed in amanner where a light emitting region provided on an active matrixsubstrate is surrounded by sealing patterns provided for a sealingsubstrate by this bonding step. Further, sealing is performed in amanner where a space surrounded by the sealing material is filled withan adhesive material 315 formed from an organic resin (FIG. 3J).

In the above steps, a light emitting device provided with a CPU, a TFTand a light emitting element can be manufactured with the plasticsubstrates 312 and 218 serving as support media. The light emittingdevice can be thin, lightweight, and flexible since the support mediaare plastic substrates. FIGS. 3A to 3J show a bottom emission type lightemitting display device in which light of the light emitting elementpasses through the plastic substrate 312. FIGS. 3A to 3J arecross-sectional views in which a display portion and a CMOS circuit thatconstitutes the CPU are overlapped. However, the present invention isnot limited thereto, and the CPU may be arranged not to overlap with thedisplay portion.

Here, an example of a light emitting device having a bottom emissionstructure is shown in FIGS. 6A and 6B.

Note that, FIG. 6A is a top view of the light emitting device and FIG.6B is a cross-sectional view of FIG. 6A taken along the line A-A′.Reference numeral 1210 denotes a substrate; 1201 indicated by the dottedline denotes a source signal line driver circuit; 1202 denotes a pixelportion; 1203 denotes gate signal line driver circuits; 1204 denotes asealing plate; 1206 indicated by the chained line denotes an integratedcircuit (e.g., CPU).

1205 is a sealing material containing conductive particles 1220 forconnecting a connection wiring 1225 with the integrated circuit 1206.The inner space sealed by the sealing material 1205 is filled with anadhesive material (typically, a transparent resin) 1207. A gap materialfor keeping a space between the sealing plate 1204 and the substrate1210 may be included in the sealing material 1205.

In addition, the inner space sealed by the sealing material 1205 may befilled with an inert gas (typically, nitride). A desiccant is providedfor the inner space to remove the trace quantity of moisture in theinner space surrounded by the sealing material 1205 so as to dry theinner space enough.

Note that, reference numeral 1208 denotes a wiring for transmittingsignals inputted to the source signal line driver circuit 1201 and thegate signal line driver circuit 1203, and the wiring receives videosignals and clock signals from an FPC (flexible printed circuit) 1209serving as an external input terminal.

Next, a cross-sectional structure is explained with reference to FIG.6B. Although a driver circuit and a pixel portion are formed over thesubstrate 1210, the source signal line driver circuit 1201 shown as thedriver circuit in FIG. 6B. The source signal line driver circuit 1201 isformed from a CMOS circuit that is a combination of an n-channel TFT1223 and a p-channel TFT 1224.

The pixel portion 1202 is formed from a plurality of pixels each ofwhich includes a switching TFT 1211, a current control TFT 1212, and afirst electrode (anode) 1213 formed from a transparent conductive filmthat is electrically connected to a drain of the current control TFT1212.

In this embodiment, the first electrode 1213 is formed so that a partthereof is to be overlapped with a connecting electrode so as to beelectrically connected to a drain region of the TFT by the connectingelectrode. It is preferable that the first electrode 1213 includes aconductive film that has transparency and a large work function (forexample, an indium tin oxide alloy (ITO), an indium oxide-zinc oxidealloy (In₂O₃—ZnO), zinc oxide (ZnO), or the like).

An insulator 1214 (referred to as a bank, partition wall, barrier, moundor the like) is formed to cover each end portion of the first electrode(anode) 1213. To improve the coverage, the upper edge portion or thelower edge portion of the insulator 1214 is formed to have a curvedsurface having a curvature. In addition, the insulator 1214 may becovered with a protective film formed of an aluminum nitride film, analuminum nitride oxide film, a thin film containing carbon as its maincomponent, or a silicon nitride film.

A layer containing an organic compound 1215 is selectively formed overthe first electrode (anode) 1213 by evaporation of an organic compoundmaterial while introducing monosilane gas. Further, a second electrode(cathode) 1216 is formed over the layer containing the organic compound1215. A small work function material (for example Al, Ag, Li, Ca, alloyssuch as, MgAg, MgIn, AlLi, inorganic compounds such as CaF₂, or CaN) maybe used as a material for forming the cathode. Thus, a light emittingelement 1218 including the first electrode (anode) 1213, the layercontaining the organic compound 1215, and the second electrode (cathode)1216, is manufactured. The light emitting element 1218 emits light inthe direction indicated by the arrow in FIG. 6B. The light emittingelement 1218 in this embodiment is a type of the one that can achievemonochrome emission of R (red), G (green), or B (blue). Full coloremission can be achieved by three light emitting elements in which eachlayer containing the organic compound that can achieve R, G, and Bemission is formed selectively.

Further, a protective laminated layer 1217 is foamed in order to sealthe light emitting element 1218. The protective laminated layer 1217 isa laminate of a first inorganic insulating film, a stress relaxationfilm, and a second inorganic insulating film.

Further, the sealing plate 1204 is bonded by the sealing material 1205and the adhesive material 1207 in vacuum or in an inert gas atmosphere,in order to seal the light emitting element 1218. It is preferable touse an epoxy resin as a material for the sealing material 1205. It isalso preferable that the sealing material 1205 and the adhesive material1207 prevent moisture or oxygen from entering thereinto as much aspossible.

A layer including the pixel portion 1202 and the driver circuits 1201and 1203 is bonded to the substrate 1210 with an adhesive layer 1222therebetween. A layer including the integrated circuit 1206 is bonded tothe sealing plate 1204 with an adhesive layer 1221 therebetween. Adisplay device having less warp can be provided by using the plasticsubstrates having the same thermal expansion coefficient as thesubstrate 1210 and the sealing plate 1204. When the display device isbended, the pair of substrates are bended together in a similar manner,and thus, lowering of the adhesiveness of the substrates can beprevented.

This embodiment can be freely combined with Embodiment Modes 1 to 3.

Embodiment 2

This embodiment shows an example of manufacturing a light emittingdevice (having a top emission structure) provided with a light emittingelement that has a layer containing an organic compound as a lightemitting layer, over a glass substrate.

Compared to a bottom emission structure, the top emission structurerequires few material layers through which light generated in the layercontaining the organic compound pass, thereby reducing stray lightbetween material layers having different reflective index.

The pixel portion is made up of a plurality of pixels each of whichcomprises a switching TFT, a current control TFT and a first electrode(anode) which is electrically connected to a drain of the currentcontrol TFT. The current control TFT may either be an n-channel TFT or ap-channel TFT, but when it is to be connected to the anode, it ispreferably be a p-channel TFT. The TFTs can be manufactured withreference to Embodiment 1. As in Embodiment 1, before the TFTs aremanufactured, a laminate of a tungsten film, a tungsten oxide film, anda silicon oxide film is formed.

Since it is constituted such that the first electrode is directlyconnected to the drain of the TFT, it is preferable that a lower layerof the first electrode be a material layer which can have an ohmiccontact with the drain containing silicon, while a top layer thereofwhich contacts the layer containing the organic compound is preferably amaterial layer which has a large work function. For example, athree-layer structure which includes a titanium nitride film, a filmcontaining aluminum as a main component, and a titanium nitride film,can have a low resistance of wiring and a favorable ohmic contact, andalso, can function as an anode. Further, as the first electrode, asingle layer of at least one film selected from a titanium nitride film,a chromium film, a tungsten film, a zinc film, a platinum film and thelike, or a laminate of three layers or more may be used.

An insulator (referred to as a bank, a partition wall, a barrier, amound or the like) is formed to cover each end portion of the firstelectrode (anode). The insulator may be formed by either an organicresin film or an insulating film containing silicon. In this embodiment,as for the insulator, an insulator is formed to have a tapered shape byusing a positive photosensitive acrylic resin film.

To improve the coverage, the upper edge portion or the bottom edgeportion of the insulator is fixated to have a curved surface havingcurvature. For example, in the case where a positive type photosensitiveacrylic is used as a material for the insulator, it is preferable thatonly the upper edge portion of the insulator is formed to have a curvedsurface having radius of curvature (from 0.2 μm to 3 μm). Either anegative type resin that is insoluble in etchant due to light or apositive type resin that is dissoluble in etchant due to light can beused as the insulator.

At the stage of forming the insulator, a separation step from thesubstrate and a transfer step to a plastic substrate are performed as inEmbodiment 1.

A layer containing an organic compound is selectively formed over thefirst electrode (anode) by evaporation using an evaporation mask orink-jetting. Further, a second electrode (cathode) is formed over thelayer containing the organic compound. As for the cathode, a materialhaving a small work function (for example Al, Ag, Li, Ca, alloys ofthereof, that is, MgAg, MgIn, AlLi, CaF₂, or CaN) may be used. In thisembodiment, as for the second electrode (cathode), a thin metal filmwhich has a small thickness is formed, and a transparent conductive film(for example, an indium oxide-tin oxide alloy (ITO), an indiumoxide-zinc oxide alloy (In₂O₃—ZnO), zinc oxide (ZnO) or the like) islaminated thereover in order to allow light to pass through. Note that,the transparent conductive film is formed in order to reduce theelectric resistance. Then, a light emitting element including the firstelectrode (anode), the layer containing the organic compound, and thesecond electrode (cathode) is manufactured. In the case where lightemitting element is emitting white light, a color filter including acolored layer and a light shielding layer (BM) may be provided to obtaina full-color display.

Further, when layers each containing an organic compound which canobtain R, G, and B luminescence respectively, are selectively formed, afull-color display can be obtained without using a color filter.

A sealing plate including a semiconductor integrated circuit is bonded,as in Embodiment 1, after the second electrode (cathode) is formed. Notethat, since this embodiment describes a top emission type, it ispreferable that the semiconductor integrated circuit and the pixelportion are designed so as not to be overlapped with each other and thespace between the sealing plate and the cathode is filled with atransparent resin.

In the case of using a transparent conductive film (such as ITO) insteadof a metal film typified by titanium nitride, a dual-emission typedisplay device can be obtained, which enables a display by making lightpass through the sealing plate and a display by making the light passthrough the plastic substrate provided with the light emitting element.Similarly in this case, it is preferable that the semiconductorintegrated circuit and the pixel portion are designed so as not to beoverlapped with each other, and the space between the sealing plate andthe cathode is preferably filled with a transparent resin.

This embodiment can be freely combined with Embodiment Modes 1 to 3 orEmbodiment 1.

Embodiment 3

This embodiment shows an example of a liquid crystal display devicehereinafter.

According to Embodiment 1, a layer to be separated including a pixel TFTis formed over a laminate of a tungsten film, a tungsten oxide film, anda silicon oxide film over a glass substrate. A driver circuit may beformed in the same step. An n-channel TFT is used as the pixel TFT, anda transparent conductive film is used as a pixel electrode. The pixelTFT may be formed by a known method.

In addition, column spacers containing an inorganic material may beprovided at a regular interval to keep the thickness of a liquid crystallayer.

Subsequently, as in Embodiment 1, the layer to be separated includingthe pixel TFT is separated from the glass substrate and transferred to aplastic substrate. Thus, an active matrix plastic substrate ismanufactured.

According to Embodiment 1, a layer to be separated including a CPU isformed over a laminate of a tungsten film, a tungsten oxide film, asilicon oxide film over a glass substrate. An opposite electrode made ofa transparent conductive film is formed besides the step ofmanufacturing the CPU.

Then, as in Embodiment 1, the layer to be separated including the CPU isseparated from the glass substrate and transferred to a plasticsubstrate. It should be noted that an optical film is used for theplastic substrate. In the liquid crystal display device, optical filmssuch as a color filter, a polarization plate, a retardation film areused. In this embodiment, the separated layer is transferred to a colorfilter in which a colored layer is patterned over the plastic substrate.Note that, the CPU is designed so as not to be arranged in a region tobe a display portion (a region where the colored layer is arranged inmatrix).

An orientation film is applied to each of faces provided with theseparated layers, and then, a rubbing treatment is performed on thefaces. A spherical spacer is sprayed if necessary.

A sealing material is applied to one of the faces. The sealing materialis arranged so as to surround at least the pixel portion. A liquidcrystal material is dropped into the region surrounded by the sealingmaterial. Appropriate doses of liquid crystals are dropped in vacuum,and as it is, the plastic substrates are preferably bonded with eachother in vacuum. The terminal electrode of the CPU provided for thecolor filter and the opposite electrode are preferably made conductivewith the terminal electrode provided for the plastic substrate byconductive particles contained in the sealing material. A conductivepaste may be used for the conduction, besides the sealing material.

According to the above-described steps, a liquid crystal display deviceis completed, in which the liquid crystal is sandwiched by the plasticsubstrate provided with the pixel electrode and the color filter.

This embodiment can be freely combined with Embodiment Modes 1 to 3 orEmbodiment 1 or 2.

Embodiment 4

A semiconductor module manufactured according to Embodiment Mode 3 isdescribed in this embodiment with reference to FIGS. 8A and 8B.

FIG. 8A is an oblique perspective view, and a second separated layer 801b and a third separated layer 801 c are formed respectively over a firstseparated layer 801 a, in such a way that edge faces thereof aredisposed in a staircase pattern. An anisotropic conductive film 803 aand an FPC 806 a are bonded in accordance with the step difference inFIG. 8A. FIG. 8B is an enlarged top view of a region surrounded by thedotted line FIG. 8A.

A wiring 803 b is provided for a surface of the anisotropic conductivefilm 803 a as shown in FIG. 8B, and is electrically connected to aterminal electrode provided for each of the separated layers. In FIG.8B, a first terminal electrode 811 a is formed to be exposed in thesurface of the first separated layer 801 a. Similarly, a second terminalelectrode 811 b is formed to be exposed in a surface of the secondseparated layer 801 b, and a third terminal electrode 811 c is formed tobe exposed in a surface of the third separated layer 801 c. In FIG. 8B,a wiring 804 that is formed on the third separated layer 801 c is shownby a dotted line, and the wiring 804 is connected to an element (notshown) included in the third separated layer 801 c.

The FPC 806 a is a film in which wirings 806 b and 806 c are formed overan insulating film and which is exposed to a laminate processing. Thewiring 806 c is a wiring for leading out the second terminal electrode811 b provided for the second separated layer 801 b. The wiring 806 bthat is provided for the FPC is a common wiring to be electricallyconnected with all terminal electrodes 811 a to 811 c.

The first separated layer 801 a, the second separated layer 801 b, andthe third separated layer 801 c include various elements (such as a thinfilm transistor, a light emitting element including a layer containingan organic compound, an element having a liquid crystal, a memoryelement, a thin film diode, a silicon-based PIN junction photoelectricconversion element, or a silicon resistance element), and is separatedby a separation method shown in Embodiment Mode 1.

When various elements are formed over the same substrate, there is arisk of lowering the yield since a design rule or a process temperaturehas more limitations. In this embodiment, a module is formed by formingelements over different heat-resistance substrates and then, separatingthe heat-resistance substrates therefrom, and laminating and bonding thesubstrates together.

The first separated layer 801 a is preferably bonded to a support medium(not shown). A plastic substrate (a resin substrate) or a glasssubstrate may be used as the support medium.

An example of a cross-sectional view of the module in FIGS. 8A and 8Bcorresponds to that in FIG. 7A.

This embodiment can be freely combined with Embodiment Modes 1 to 3 orEmbodiments 1 to 3.

Embodiment 5

Various modules (an active matrix EL module, a passive matrix EL module,a liquid crystal display device and an active matrix EC module) can becompleted by implementing the present invention. Namely, all of theelectronics into which the various modules are built is completed byimplementing the present invention.

Following can be given as such electronics: video cameras; digitalcameras; head mounted displays (goggle type displays); car navigationsystems; projectors; car stereos; personal computers; portableinformation terminals (mobile computers, mobile phones or electronicbooks etc.) etc. Examples of these are shown in FIGS. 9A to 9E and 10Ato 10C.

FIG. 9A is a personal computer including a main body 2001, an imageinput section 2002, a display portion 2003, a keyboard 2004, and thelike. The personal computer can be more light-weight according to thepresent invention.

FIG. 9B is a video camera including a main body 2101, a display portion2102, a voice input section 2103, operation switches 2104, a battery2105, an image receiving section 2106, and the like. The video cameracan be more light-weight according to the present invention.

FIG. 9C is a game machine including a main body 2201, operation switches2204, a display portion 2205, and the like.

FIG. 9D is a player using a recording medium in which a program isrecorded (hereinafter referred to as a recording medium), which includesa main body 2401, a display portion 2402, a speaker section 2403, arecording medium 2404, and operation switches 2405, and the like. Thisplayer uses DVD (digital versatile disc), CD, etc. as the recordingmedium, and makes it possible to perform music appreciation, filmappreciation, games and use for Internet.

FIG. 9E is a digital camera including a main body 2501, a displayportion 2502, a view finder 2503, operation switches 2504, an imagereceiving section (not shown), and the like. The digital camera can bemore light-weight according to the present invention.

FIG. 10A is a mobile phone including a main body 2901, a voice outputsection 2902, a voice input section 2903, a display portion 2904,operation switches 2905, an antenna 2906, an image input section (CCD,image sensor, etc.) 2907 and the like.

FIG. 10B is a portable book (electronic book) including a main body3001, display portions 3002 and 3003, a recording medium 3004, operationswitches 3005, an antenna 3006, and the like. The portable book can bemore light-weight according to the present invention.

FIG. 10C is a display unit including a main body 3101, a supportingsection 3102, a display portion 3103, and the like.

In addition, the display unit shown in FIG. 10C has small andmedium-sized or large-sized screen, for example a size of from 5 inchesto 20 inches. Further, for the sake of manufacturing the display portionwith such sizes, it is preferable to mass-produce by gang printing byusing a substrate with one meter on a side.

As described above, the applicable range of the present invention isextremely large, and the present invention can be applied to electronicsin various areas. Note that, the electronics in this embodiment can beachieved by utilizing any combination of constitutions in EmbodimentMode 1 or 2, and Embodiments 1 to 4.

This application is based on Japanese Patent Application serial no.2003-069742 filed in Japan Patent Office on 14 Mar. 2003, the contentsof which are hereby incorporated by reference.

Although the present invention has been fully described by way ofEmbodiment Modes and Embodiments with reference to the accompanyingdrawings, it is to be understood that various changes and modificationswill be apparent to those skilled in the art. Therefore, unlessotherwise such changes and modifications depart from the scope of thepresent invention hereinafter defined, they should be constructed asbeing included therein.

1. A semiconductor device comprising: a pixel portion and a drivercircuit formed over a first substrate, the pixel portion comprising: afirst thin film transistor formed over the first substrate; a firstelectrode formed over and connected to the first thin film transistor;an EL layer formed over the first electrode; and a second electrodeformed over the EL layer; the driver circuit being capable of drivingthe pixel portion comprising a second thin film transistor over thefirst substrate; a semiconductor integrated circuit comprising a thirdthin film transistor and formed below a second substrate; and a sealingmaterial formed between the first substrate and the second substrate,wherein the semiconductor integrated circuit overlaps with the drivercircuit and the pixel portion.
 2. The semiconductor device according toclaim 1, wherein each of the first substrate and the second substrate isa plastic substrate.
 3. The semiconductor device according to claim 1,wherein the sealing material comprises a conductive particle.
 4. Thesemiconductor device according to claim 3, further comprising an FPCconnected to the semiconductor integrated circuit through the conductiveparticle.
 5. The semiconductor device according to claim 1, furthercomprising: a first adhesive layer formed between the first substrateand the pixel portion; and a second adhesive layer formed between thesecond substrate and the semiconductor integrated circuit.
 6. Anelectronic device having the semiconductor device according to claim 1,wherein the electronic device is selected from the group consisting of avideo camera, a digital camera, a head mounted display, a car navigationsystem, a car stereo, a personal computer, a mobile computer, a mobilephone and an electric book.
 7. A semiconductor device comprising: apixel portion comprising a light-emitting element over a firstsubstrate; a driver circuit over the first substrate; a second substrateprovided with a semiconductor integrated circuit; a first adhesive layerbetween the first substrate and the second substrate; a second adhesivelayer between the light-emitting element and the first substrate; and athird adhesive layer between the semiconductor integrated circuit andthe second substrate, wherein the semiconductor integrated circuitoverlaps with the driver circuit, and wherein the semiconductorintegrated circuit is not overlapped with the pixel portion.
 8. Asemiconductor device according to claim 7, wherein the first substratecomprises an organic resin material.
 9. A semiconductor device accordingto claim 7, wherein the semiconductor integrated circuit comprises: acentral processing unit comprising: a control unit; and an arithmeticunit; and a memory unit, and wherein the central processing unitcomprises a plurality of thin film transistors.
 10. A semiconductordevice according to claim 7, wherein the semiconductor integratedcircuit comprises a thin film diode.
 11. A semiconductor deviceaccording to claim 7, wherein the semiconductor integrated circuitcomprises a silicon-based PIN junction photoelectric conversion element.12. A semiconductor device according to claim 7, wherein thesemiconductor integrated circuit comprises a silicon resistance element.13. A semiconductor device comprising: a pixel portion comprising alight-emitting element over a first substrate; a driver circuit over thefirst substrate; a second substrate provided with a semiconductorintegrated circuit; wherein the semiconductor integrated circuitoverlaps with the driver circuit, and wherein the semiconductorintegrated circuit is not overlapped with the pixel portion.
 14. Asemiconductor device according to claim 13, wherein the first substratecomprises an organic resin material.
 15. A semiconductor deviceaccording to claim 13, wherein the semiconductor integrated circuitcomprises: a central processing unit comprising: a control unit; and anarithmetic unit; and a memory unit, and wherein the central processingunit comprises a plurality of thin film transistors.
 16. A semiconductordevice according to claim 13, wherein the semiconductor integratedcircuit comprises a thin film diode.
 17. A semiconductor deviceaccording to claim 13, wherein the semiconductor integrated circuitcomprises a silicon-based PIN junction photoelectric conversion element.18. A semiconductor device according to claim 13, wherein thesemiconductor integrated circuit comprises a silicon resistance element.